Dose Finding and Pharmacokinetics/Pharmacodynamics Study of Apatinib in the Treatment of Advanced Colorectal Cancer

RATIONALE: Apatinib is a tyrosin-inhibitor agent targeting at vascular endothelial growth factor receptor (VEGFR), and it’s anti-angiogenesis effect has been viewed in preclinical tests. The investigators’ phase I study has shown that the drug’s toxicity is manageable. PURPOSE: 1. Studying how well Apatinib works in treating patients. 2. Finding the efficacy and safety of 500 mg or 750mg Apatinib. 3. Pharmacokinetics/Pharmacodynamics(PK/PD). 4. Exploring new outcome measures of antiangiogenic drugs.